Mirroring controller, storage device, and mirroring control method

Abstract

A mirroring controller includes a copy controller that selects one memory from among the plurality of memories as a copy source memory and copies data from the copy source memory to at least one copy target memory; and an I/O mirroring controller that copies, when a read request to the copy source memory is issued from an upper layer during copying by the copy controller, data from an area corresponding to the read request to the copy target memory, wherein, when processing corresponding to the read request to the copy source memory from the upper layer results in an error at the copy source memory during the copying by the copy controller, the copy controller controls the copy source memory so as to become unusable, and controls at least one copy target memory so as to act as a memory.

1 . A mirroring controller that maintains data redundancy by a plurality of memories, the mirroring controller comprising:
 a copy controller that selects one memory from among the plurality of memories as a copy source memory and, to obtain data equivalence between the plurality of memories, copies data from the copy source memory to at least one copy target memory that is different from the copy source memory, among the plurality of memories; and   an I/O mirroring controller that copies, when a read request to the copy source memory is issued from an upper layer during copying by the copy controller, data from an area corresponding to the read request to the copy target memory,   wherein, when processing corresponding to the read request to the copy source memory from the upper layer results in an error at the copy source memory during the copying by the copy controller, the copy controller controls the copy source memory so as to become unusable, and controls at least one copy target memory so as to act as a memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         2 . The mirroring controller according to  claim 1 ,
 wherein, when an error occurs in reading data from the area corresponding to the read request when the data in the area is copied to the copy target memory, the I/O mirroring controller controls the copy source memory so as to become unusable, and controls at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         3 . The mirroring controller according to  claim 1 ,
 wherein, when a write request to the plurality of memories is issued from the upper layer and a write error occurs in at least one of the plurality of memories during the copying by the copy controller, the copy controller controls the copy source memory so as to become unusable when the write error occurs at the copy source memory, and controls the at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         4 . The mirroring controller according to  claim 1 ,
 wherein, only when the read request is a read request for an area where the copying by the copy controller has not been completed, the I/O mirroring controller copies the data in the area to the copy target memory.   
     
     
         5 . The mirroring controller according to  claim 1 ,
 wherein, when a read error with respect to the read request occurs at the copy source memory during the copying by the copy controller, the copy controller copies data in the copy target memory controlled so as to act as the memory that performs the processing corresponding to the read request from the upper layer, to another copy target memory to continue the copying.   
     
     
         6 . A storage device comprising:
 a plurality of memories; and   a mirroring controller that maintains data redundancy by the plurality of memories,   wherein the mirroring controller includes:   a copy controller that selects one memory from among the plurality of memories as a copy source memory and, to obtain data equivalence between the plurality of memories, copies data from the copy source memory to at least one copy target memory that is different from the copy source memory, among the plurality of memories; and   an I/O mirroring controller that copies, when a read request to the copy source memory is issued from an upper layer during copying by the copy controller, data from an area corresponding to the read request to the copy target memory,   wherein, when processing corresponding to the read request to the copy source memory from the upper layer results in an error at the copy source memory during the copying by the copy controller, the copy controller controls the copy source memory so as to become unusable, and controls at least one copy target memory so as to act as a memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         7 . The storage device according to  claim 6 ,
 wherein, when an error occurs in reading data from the area corresponding to the read request when the data in the area is copied to the copy target memory, the I/O mirroring controller controls the copy source memory so as to become unusable, and controls at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         8 . The storage device according to  claim 6 ,
 wherein, when a write request to the plurality of memories is issued from the upper layer and a write error occurs in at least one of the plurality of memories during the copying by the copy controller, the copy controller controls the copy source memory so as to become unusable when the write error occurs at the copy source memory, and controls the at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         9 . The storage device according to  claim 6 ,
 wherein, only when the read request is a read request for an area where the copying by the copy controller has not been completed, the I/O mirroring controller copies the data in the area to the copy target memory.   
     
     
         10 . The storage device according to  claim 6 ,
 wherein, when a read error with respect to the read request occurs at the copy source memory during the copying by the copy controller, the copy controller copies data in the copy target memory controlled so as to act as the memory that performs the processing corresponding to the read request from the upper layer, to another copy target memory to continue the copying.   
     
     
         11 . A mirroring control method for maintaining data redundancy by a plurality of memories, the method comprising:
 selecting one memory from among the plurality of memories as a copy source memory to obtain data equivalence between the plurality of memories;   copying data from the copy source memory to at least one copy target memory that is different from the copy source memory, among the plurality of memories;   copying, when a read request to the copy source memory is issued from an upper layer during copying to obtain the data equivalence, data from an area corresponding to the read request to the copy target memory; and   when processing corresponding to the read request to the copy source memory from the upper layer results in an error at the copy source memory during the copying to obtain the data equivalence, controlling the copy source memory to become unusable, and controlling at least one copy target memory so as to act as a memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         12 . The mirroring control method according to  claim 11 , further comprising:
 when an error occurs in reading data from the area corresponding to the read request when the data in the area is copied to the copy target memory, controlling the copy source memory so as to become unusable, and controlling at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         13 . The mirroring control method according to  claim 11 , further comprising:
 when a write request to the plurality of memories is issued from the upper layer and a write error occurs in at least one of the plurality of memories during the copying to obtain the data equivalence, controlling the copy source memory so as to become unusable when the write error occurs at the copy source memory, and controlling the at least one copy target memory so as to act as the memory that performs the processing corresponding to the read request from the upper layer.   
     
     
         14 . The mirroring control method according to  claim 11 , further comprising:
 only when the read request is a read request for an area where the copying to obtain the data equivalence has not been completed, copying the data in the area to the copy target memory.   
     
     
         15 . The mirroring controller according to  claim 11 , further comprising:
 when a read error with respect to the read request occurs at the copy source memory during the copying to obtain the data equivalence, copying data in the copy target memory controlled so as to act as the memory that performs the processing corresponding to the read request from the upper layer, to another copy target memory to continue the copying.